The behavior with multiple HDMI 1 entries is known to me with SONY Android TVs. There can some more sub devices displayed if you have additional CEC compatible devices connected to your DENON AVR. On that way you are able to switch between the different CEC sources on your AVR via TV remote. Also I can confirm that not all (but the most) CEC keys are working if the TV is only switched to "HDMI 1" and not to the sub entry "HDMI 1 KODI ...". Maybe you have installed a firmware update for the TV, so that something has been changed?
The TalkBack feature (if available) is disabled? https://www.sony.com/electronics/support/articles/00269974
Regarding the irritating double entries for the CEC adapter in the input settings menu, you should switch to a newer version than the official version 12.0.1, as this contains the fix: https://test.libreelec.tv/12.0/RPi/RPi5/…-0803b93.img.gz